High Quality Content by WIKIPEDIA articles! In physics, the Poynting vector can be thought of as representing the directional energy flux density (the rate of energy transfer per unit area, in W/m2) of an electromagnetic field. It is named after its inventor John Henry Poynting. Oliver Heaviside and Nikolay Umov independently co-invented the Poynting vector. In Poynting`s original paper and in many textbooks it is defined as